In certain logic circuits an output data state is produced at an output terminal. The output terminal is then connected to deliver the output signal to other circuit elements. The output terminal is typically driven to high and low voltage states. If the output terminal should become grounded when the circuit is attempting to drive it to a high voltage state there may be a heavy current flow through the driving circuit. If no means are provided for limiting current flow through the output terminal, the surge of current can frequently be sufficient to damage the driving circuit. The provision of a current limiting resistor, however, has the disadvantage that it slows the driver circuit in driving the output terminal to the desired voltage state.
In view of the above problems there exists a need for a current limiting driver circuit in which the output terminal can be rapidly driven to the highest voltage state required while at the same time having a limitation on the current which can be transmitted through the output terminal to prevent damaging the driver circuit or related circuits.